1. Technical Field
This device relates to truck tonneau covers that use a lightweight perimeter frame around the truck bed over which a canvas cloth material is stretched defining a cover. Heretofore, the canvas cloth cover had to be partially removed from the frame for limited access to the truck bed.
2. Description of Prior Art
Prior art devices of this type have relied on a variety of hard, semi-hard cover elements and frames that were hinged to the truck bed for tilt-up access to the rear of the bed. The covers typically have a spring assembly and support rods to hold the rigid hard cover above the bed with a variety of different cover constructions, hinge elements and supporting assemblies, see for example U.S. Pat. Nos. 2,989,340, 3,762,762, 3,785,698, 4,083,596, 4,762,360 and 4,496,184.
In U.S. Pat. No. 2,989,340 a quick detachable hinged structure is disclosed that uses spring mounted hinge pin assembly bolted to the forward wall of the truck bed and coil spring rods that secure the top to the respective side walls of the bed.
U.S. Pat. No. 3,762,762 is directed towards a cover and lifting mechanism for a pick-up truck wherein a rigid hard top is hinged from the truck bed by a pair of pivoted brackets secured to the bed frame and front wall of the bed with stanchions springs and pin assembly secured to connect the arms to the top.
U.S. Pat. No. 3,785,698 discloses a cover top for a pick-up truck bed wherein a removable hinge cover has an axial hinge with a spring portion and overbearing hook portion. Support rods extend from the rear of the top for sliding registration in a horizontal spring loaded mounting channel in the side walls of the truck bed.
A raiseable topper can be seen in U.S. Pat. No. 4,083,596 in which a solid rigid cover top is hinged to the front wall of the truck bed from a first position, to a second position wherein the cover member is supported substantially above the bed via multiple pivoted spring-loaded support arms extending from each end of the rigid cover to fixed pivot points on the bed.
In U.S. Pat. No. 4,762,360 a de-mountable pick-up truck tonneau cover can be seen wherein spring-loaded pins are mounted on the interior of the cover for releasable engagement with the sides of the cargo box bed so that once the pins are retracted against the springs, the tonneau cover can be fully removed.
Finally, in U.S. Pat. No. 4,496,184 a two-tiered tonneau cover frame is shown that has a lower frame, U-shaped bed engagement frame and an upper elevated U-shaped frame extending therefrom. Canvas material is stretched over the frames in alternate forms of the invention and the frames are pivotally connected to the bed at two opposing pivot points.